Conventional knitting machines generally employ either a plurality of spring beard or latch needles carried in a cylinder. In either case the needles are reciprocated in a manner so that the beard or latch is sequentially opened and closed so the hook of the needle may grasp a segment of thread or yarn being laid under the hook of the needle at the proper point in its cycle, and pull it into a loop, pull the new loop through a previously formed loop, and cast off a previously formed loop. The rate of this reciprocative movement of the needles, which must be coordinated with a mechanism feeding thread to the needles, is the primary limiting factor on the production rate of the knitting machines. Also, this reciprocative movement induces vibrations which must be designed for. In addition, the lateral distance between the thread feeding points on a reciprocating machine must be large enough to accommodate the lateral axial traversing of the needles in the ramped raceways required to produce the reciprocating needle movement.
As a means for eliminating some of these problems, German patent 1,809,347, issued Dec. 23, 1970, proposes providing rotary needles which include at least two hooked gripping elements and which are supported between and are rotated by three triangularly disposed drive shafts drivingly engaging the periphery of the needles. Such a three point drive and suspension system becomes unstable when the open portion of a hook section passes under one of the supporting drive shafts, i.e. the needle is radially displaced so that the line between the other two supporting shafts does not pass through the center of rotation resulting in an eccentric rotation of the needles. Also, the needles can only be rotated in one direction and at a common speed, thereby limiting the type of knitted fabric and/or patterns capable of being produced.